We recently enabled the ability for your ads to belong to several categories. Be sure to check only those categories appropriate for your ads. You can see this new capability shown in the picture below:

We enable this new ability because we think it's useful for you as an advertiser and for the searchers. Some ads necessarily belong not only to one category but also to other categories such as "Job Offers". For example, a certain company is hiring people with different fields of jobs: Architect, Human Resource, Inventory Staff and many more. And if a job searcher looks for the said job, it will be easier for him/her to locate those jobs that belong to appropriate categories.

Thus, it only shows how useful the "ability for your ads to belong to several categories" for both parties: advertiser and searcher.